The attorneys general of California and NY announced Thursday that they are joining the legal defense of the emissions standards.

Hear more from Daniel Howes about the future of environmental regulations for vehicle makers in our interview above.

In Michigan, Trump delivered a campaign-style speech in which he railed against big trade agreements, specifically NAFTA and the recent Trans-Pacific Partnership, laying out in stark terms his view of how the pacts had hurt the US auto industry and its workers. Jerry Brown and environmentalists depict as crucial to control pollution and to reduce the emission of gases believed to contribute to global warming. The Obama administration cancelled the mid-term review before the former US president left office amid fears Trump would seek to have them modified or rolled back, which Marchionne considers unfair. But Donald Trump maintains that it's those standards that are costing USA auto manufacturing jobs. Both said that it is too late to turn back the clock on electric cars, that auto manufacturers need to be good environmental citizens, and that fuel-efficient cars can save consumers a lot of money. The Corporate Average Fuel Economy (CAFE) standards, which were implemented decades ago but accelerated under President Obama, call for automakers to reach a fleetwide average 54.5 miles per gallon by 2025. She added that the analysis of the standards "has shown that the greenhouse gas emissions standards for cars and light trucks remain affordable and effective through 2025, and will save American drivers billions of dollars at the pump while protecting our health and the environment".

The Trump administration downplayed any potential fight, saying officials have more than a year to resolve differences. The current standards helped the auto companies move from bankruptcy to profitability, and there is no reason they can not be met.

Within two weeks, Smith had a new job as legal director of civil rights group Muslim Advocates and was drafting briefs for a successful court challenge to the ban, joining other former top Obama administration lawyer s now fighting Trump. When efficiency rules were relaxed in the mid-1980s, foreign automakers only had about 25 percent of the market, but now they have 55 percent.

That means California would end up setting national policy.

Complying with tougher standards would lead to declining new vehicle sales and higher auto prices that drain consumer cash from other parts of the economy, SPEA researchers found.

"High octane, low carbon fuels can play a significant role in helping to meet fuel economy targets in the future", RFA President Bob Dinneen said in a statement.

Trump said he had kept his promise to withdraw the USA from the TPP, an agreement that former President Barack Obama pursued with 11 other Pacific Rim nations.

A senior White House official said Tuesday that the administration wants to negotiate one national standard. He spoke on condition of anonymity even though Trump has criticized the use of unnamed sources.

"We're going to do some wonderful work with you but you're going to have to help us with jobs", he said.